Design Of Unit Cells for Groove Gap Waveguide at Millimeter Wave Spectrum

In this paper, a new design of unit cells is proposed for application of groove gap waveguide (GGW) at millimeter Wave (mm-wave) spectrum. In this research work, we designed a band gap using periodic structure that increased the bandwidth of transmission lines over a vast spectrum. To design unit cells for gap waveguides, dispersion characteristics are studied using an eigen mode solver of CST Microwave Studio. Dispersion diagram provides the cutoff band, depicting no propagating modes are present between cutoff frequencies. For this purpose, bed of nails unit cell is augmented to enhance the bandwidth achieved by Electromagnetic band-gap (EBG) structure. Two new unit cell designs based on Mushroom type EBG are presented. For both designs GGW with straight, single 90° bend and double 90° bends have been simulated for evaluation of proposed designs and compared with standard bed of nails EBG structure. Simulation results showed that bandwidth enhancement of 2.365 GHz for proposed mushroom type EBG unit cell and 1.742 GHz for proposed hybrid mushroom type EBG unit cell is achieved in comparison to straight pin..